There are many possible symptoms of post-polio syndrome (PPS). The exact symptoms you may have depend on many factors, including which muscles were affected by the original polio infection. For most people, muscle weakness caused by PPS gets worse very gradually and may take many years to become noticeable. You may go through long periods of stability when your symptoms do not get any worse.

The symptoms of PPS may resemble those of amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease), a disease of the nerves that control movement (motor neurons) that usually leads to death within several years. Post-polio syndrome is not a form of ALS and usually is not life-threatening.

The most common symptoms of post-polio syndrome are:

• New muscle weakness.
• Fatigue.
• Muscle and joint pain.

New muscle weakness

Most people who have PPS develop new muscle weakness. In some cases the weakness is caused by wasting away (atrophy) of the muscle. This new muscle weakness is sometimes called post-polio progressive muscular atrophy.

Muscle weakness is most common in the muscles that were originally affected by polio. But many people with PPS find that muscles that were not paralyzed by polio are getting weaker as well. This is not because PPS is spreading. Instead, experts believe that these muscles were indeed affected by the polio virus, but the effect was not as severe. In fact, in most cases the person never knew that polio had affected the nerves that control those muscles.

In some cases new muscle weakness is caused by underuse of that muscle. This may happen if you stop using the muscle because of fatigue or pain in your joints or muscles.

Fatigue

Most people with PPS experience fatigue, which is a feeling of exhaustion, after a short period of activity. You may find that activities you were once were able to do without getting tired now cause fatigue. You may feel tired, lack energy, or have a heavy sensation in your muscles. When fatigue is severe, it can affect your ability to think or concentrate. You may even feel confused or sleepy. A short rest after activity usually can reduce your fatigue.

Muscle or joint pain

Many people with PPS have muscle or joint pain.

Even when it seems that you have completely recovered from polio, your muscles tend to be weaker than normal. To make up for this weakness, other muscles have to work harder. This is especially noticeable when you are walking. When muscles have to work overtime this way, it puts extra stress on muscles, joints, and tendons.

Over time, this extra stress may lead to muscle aches or cramping from overuse and joint or tendon pain from excess wear on joints and tendons. In many cases the pain is severe enough to limit your use of that part of your body. This resulting decrease in activity can lead to muscle weakness and can create a cycle of weakness, overuse of other muscles, and increased pain.